Session: 04-26 Atomization and Spray Combustion II
Paper Number: 125052
125052 - A Modal Analysis of Spray Structures From a Transversely Injected Liquid Jet in Subsonic and Supersonic Crossflows
Flow instabilities in high-Reynolds flows are difficult to characterize because the increasingly chaotic interactions of fluid particles allow for larger variety and superpositions of flow patterns. These are especially underexplored in transversely injected liquid jets, which are a popular mixing strategy for high-Reynolds gaseous flows. This study utilizes proper orthogonal decomposition (POD) and spectral POD (SPOD) to identify periodic flow patterns in experimental spray images. A liquid ethanol jet is injected into both a linear subsonic and an expanding Mach 2 gaseous crossflow with plain-orifice injectors of 0.5, 1, and 2mm diameter. The subsonic test section is rectangular with a 50 cm length and a 23x17 cm cross section; a contoured insert is installed in this rectangular test section to generate the supersonic flow path with a 2.54x23 cm throat area. Across both regimes, crossflow mass flows vary from 0.5 to 12 kg/s with injectant momentum flux ratios between 0.3 and 180. A high-speed camera is used with both shadowgraph and schlieren imaging systems to collect transmittance contours of the spray at 25 kHz, and fast-response pressure transducers are used to measure static pressure fluctuations both upstream and downstream of the flush-mounted injector. Dagger-shaped peaks in the spray profile are identified in subsonic crossflows, and their passing frequency is correlated to the measured pressure fluctuations. The supersonic crossflow features smoother hump-shaped peaks. Bulk velocity of these spray structures is measured with image velocimetry, and trends in the size and frequency are related to the crossflow velocity and injectant momentum flux ratio.
Presenting Author: Aubrey McKelvy Purdue University
Presenting Author Biography: Aubrey McKelvy is a PhD candidate at Purdue University and works with the PETAL research group out of Zucrow labs. His research focuses on liquid jet break up in high momentum gaseous crossflows.
Authors:
Aubrey McKelvy Purdue UniversityJames Braun North Carolina State University
Guillermo Paniagua Purdue University
Etienne Choquet MBDA
Thierry Andre MBDA
Francois Falempin MBDA
A Modal Analysis of Spray Structures From a Transversely Injected Liquid Jet in Subsonic and Supersonic Crossflows
Paper Type
Technical Paper Publication